The King joked today that he was glad to be ‘out of my cage’ as he embarked on his first military engagement since announcing a comeback to public-facing duties.

Charles met military staff and their families at a training base for the Army’s Royal Engineers in Surrey, while his son Prince William was on engagements in Cornwall and his wife Queen Camilla hosted a reception for an animal charity in London.

The King was in jovial form, with one highlight seeing him ask a group of parents: ‘I’m glad I got all these children out of school, are you going back after?’ A child replied: ‘No, day off today.’ Charles then said: ‘Oh, you see? I do have my uses occasionally.’

It comes as Prince Harry prepares to fly onto Nigeria after seeing neither during his quick visit to London which saw him attend a range of Invictus Games events.

William visited Newquay this afternoon where his Duchy of Cornwall has been building its first ever housing project to help address homelessness in Nansledan.

He then went to Fistral Beach, putting on sunglasses in the glorious weather while he spoke with young lifesavers and played volleyball. A nine-year-old boy named Phoenix Kanes asked him to sign his plaster cast on his arm – and the Prince obliged.

Back in London, Camilla posed for photographs with guests and mini ponies as she hosted a reception at Buckingham Palace to mark the 90th anniversary of Brooke, a charity dedicated to improving the lives of working horses, donkeys, and mules.

King Charles III during a visit to Gibraltar Barracks in Minley, Hampshire, this afternoon

King Charles III jokes with a group of families during a visit to Gibraltar Barracks in Minley, Hampshire, today to meet the staff and families of the 3 Royal School of Military Engineering

King Charles III during a visit to Gibraltar Barracks in Minley, Hampshire, this afternoon

As he was led into the officers’ mess by Lieutenant Colonel Robert Grant, commanding officer of 3RSME, King Charles said to him today: ‘I do apologise for taking you by surprise, when this opportunity appeared and I had been allowed out of my cage, I wanted to come to have a look’

King Charles III is shown a drawing of himself by Louie Bacon, six, during a visit to Gibraltar Barracks in Minley, Hampshire, this afternoon

In Surrey, the King apologised to the Army for making a visit at the last moment but said he had wanted to come as soon as he had been ‘allowed out of my cage’.

Charles made his comments during a visit to the 3 Royal School of Military Engineering (3RSME) at Gibraltar Barracks in Minley this afternoon.

The King, who is Colonel-in-Chief of the Royal Engineers, was met by the Lord Lieutenant Nigel Atkinson and Major General Eldon Millar before he received a salute from a Quarter Guard comprising officers from the school.

As he was led into the officers’ mess by Lieutenant Colonel Robert Grant, commanding officer of 3RSME, the King said to him: ‘I do apologise for taking you by surprise, when this opportunity appeared and I had been allowed out of my cage, I wanted to come to have a look.’

Lt Col Grant told the PA news agency: ‘We only had six days to pull this together but the only answer from us was ‘yes’. There was a palpable sense of excitement as you saw the units spark into life for the visit.’

The King then met with groups of engineers and their families where he learnt about their experiences training at the school and the support they receive from their loved ones.

Speaking to heavily-pregnant Sophie Mairs, 37, who is six weeks until het due date, the King joked: ‘Are you sure you should be here today?’

Sophie, whse husband WO2 Barry Mairs, 38, is in the Engineers, said afterwards: ‘I said I couldn’t miss it. It’s not every day the King comes to where your husband works.’

The King also shared a joke with Natalie Newman, the wife of Corporal Joseph Newman, when she told him that they had three children. Charles told her: ‘Nothing a strong drink won’t help.’

When Cpl Newman told him that his role was as an electrician, he said to Mrs Newman: ‘Terribly helpful to have an electrician around.’

She replied jokingly: ‘Well, you say that!’

Speaking afterwards, Mrs Newman, 34, from Poole, Dorset, said: ‘It was amazing, nerve-wracking, but amazing.

‘I just said how many children I had, I said I had three children, and he said ‘It was nothing a strong drink won’t help’.

‘He was really funny, he appeared absolutely fine and upbeat.’

Cpl Newman, 32, said: ‘He is a really lovely person, he liked to engage with you, it wasn’t a fleeting chat, it was an in-depth conversation.’